The article analyses this issue from the perspective of the liability relations. The division itself of legal regulation in the area of liability relations between two codes (Civil Code and Commercial Code) generates many problems. In the last years these relations were most significantly influenced by legal regulation of the consumer protection, which substantially intervened into the Commercial Code and redefined its scope. The article points out to multiple issues of fundamental importance, which are reflected in the following areas: the relation between the Civil Code and the Commercial Code; modification of selection of the Commercial Code by agreement of the parties; acceptability of the fiction that provisions of the Civil Code are always more favourable for the consumer. In the period of high fragmentation and variability of legal provisions it underlines the need to pay attention to the quality of their content and the method of their integration into the system of law, including the area of consumer law. All this considerably influences the interpretation and application of legal norms and their observance.